The invention relates to the field of valves, and in particular to drain cocks for releasing gas or liquid from pressurized vessels.
Drain cocks currently used for releasing gas or liquid from vessels typically provide only a single seal, a double seal formed exclusively by contact with deformable material, or a double seal formed by line contact with non-deformable material. Single seal drain cocks, such as in U.S. Pat. No. 1,465,952, to Smith et al, issued Aug. 28, 1923, do not provide a back up seal for failsafe protection from gas or fluid leakage in high pressure environments, such as air compressors. Double seal drain cocks with seals consisting of deformable material exclusively, such as in U.S. Pat. No. 4,529,167, to Harrison et al, issued Jul. 16, 1985, often require costly replacement of damaged or permanently deformed sealing elements due to the high forces to which they are subjected. Double seal drain cocks utilizing line contact seals between non-deformable material, such as U.S. Pat. No. 4,307,748, to Mathias, issued Dec. 29,1981, are similarly susceptible to costly replacement and inadequate sealing. Accordingly, the present invention overcomes the deficiencies of the prior art by providing a double seal drain cock that utilizes a surface contact seal between two non-deformable materials.